The conventional digital photographic system theoretically can only obtain the clear image of a single object plane. The limited width of a photodetector unit can extend the scope of this clear imaging to a certain depth, i.e. depth of field. During conventional imaging, the light radiation emitted by the entire aperture of the optical system is usually integrated directly, so that the scope of the depth of field is limited by the size of the aperture. In order to obtain a clear image with a large depth of field, the imaging aperture must be narrowed, which will in turn cause a decrease in the resolution of the image and a loss in the signal-to-noise ratio of the image. Meanwhile, given a certain aperture size, in order to obtain clear images at different depth positions, mechanical focusing must be performed before imaging.
In the light field photographic system, images at any depth position can be obtained by digital focusing, so mechanical focusing is no longer necessary, and the problem of the depth of field being limited by the aperture size is also solved. Nevertheless, the resolution of imaging of the light field photographic system is lower than the resolution of imaging of the conventional photographic system.